[feat](trx-server): persist 24h decode history across restarts

Move persistent history from trx-client to trx-server where decode
events originate. History for AIS, VDES, APRS, CW, FT8, and WSPR is
loaded from ~/.local/cache/trx-rs/history.db at startup and flushed
to disk every 60 seconds. CW events are now also stored in
DecoderHistories and replayed to connecting clients, consistent with
all other decoder types.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>

src/trx-client/Cargo.toml

@@ -15,7 +15,6 @@ toml = { workspace = true }
 tracing = { workspace = true }
 clap = { workspace = true, features = ["derive"] }
 dirs = "6"
-pickledb = "0.5"
 bytes = "1"
 cpal = "0.15"
 opus = "0.3"

src/trx-client/src/main.rs

@@ -5,7 +5,6 @@
 mod audio_bridge;
 mod audio_client;
 mod config;
-mod history_store;
 mod remote_client;
 
 use std::collections::HashMap;
@@ -125,17 +124,6 @@ async fn async_init() -> DynResult<AppState> {
     let mut frontend_reg_ctx = FrontendRegistrationContext::new();
     let mut frontend_runtime = FrontendRuntimeContext::new();
 
-    // Load persisted decode history before frontends start.
-    let db = {
-        let db = history_store::open_db();
-        history_store::load_all(&db, &mut frontend_runtime);
-        tracing::info!(
-            "Loaded decode history from {}",
-            history_store::db_path().display()
-        );
-        std::sync::Arc::new(std::sync::Mutex::new(db))
-    };
-
     register_http_frontend(&mut frontend_reg_ctx);
     register_http_json_frontend(&mut frontend_reg_ctx);
     register_rigctl_frontend(&mut frontend_reg_ctx);
@@ -349,9 +337,6 @@ async fn async_init() -> DynResult<AppState> {
         );
     }
 
-    // Flush in-memory history to disk every 60 seconds.
-    history_store::spawn_flush_task(db.clone(), frontend_runtime_ctx.clone());
-
     // Spawn frontends with runtime context
     for frontend in &frontends {
         let frontend_state_rx = state_rx.clone();